1. Field of the Invention
The invention relates to a multiple tool holding automatically indexing tool magazine used by a metal processing machine of the type that incorporates an automatic tool change function, specifically, a tool magazine that can be used to store a greater number of tools in a smaller space than conventional tool magazines.
2. Description of the Related Art
Japanese Unexamined Patent Application No. 2000-94252 teaches a tool magazine that performs the same automatic tool indexing function as the invention. The tool magazine put forth in the aforesaid patent is comprised of multiple tool holding pots radially arranged on the outer surface of a round table-like structure. Because the tool holding pots are arranged in a circular pattern, the size of the entire magazine increases as the number of tools it is designed to hold increases, thus causing the tool magazine to occupy more space in relation to the number of tools held therein.
The following structure has been used in an effort to reduce the space occupied by the aforesaid type of tool magazine. Two rotating sprockets are oriented at a mutually respective distance so as to establish a space there between, and a chain is placed over both sprockets and tensioned adequately so as not to slip between the sprockets, thus forming a movable oval shaped track structure onto which tool holding pots are attached at specific intervals. This oval shaped track structure traverses as means of bringing the desired tool pot (and tool contained therein) to a tool removal station. A pick-up device then extracts the tool and attaches it to the metal processing machine.
There is a problem, however, in that the number of tool pots that can be installed to the aforesaid oval track structure is limited by the length of that structure, thus necessitating the use of multiple tool magazines in cases where it is desired to use more tools than a single magazine can accommodate, and further necessitating the need for a relatively large space to accommodate these multiple tool magazines. Moreover, the tool magazine control system becomes more complicated when multiple tool magazines are used.
Furthermore, when the track and tool pots are in motion, all of the tools must be moved in order to bring one tool to the exchange position. As a result, there is a large amount of inertia to be overcome as the drive system must move all of the tools when a tool indexing operation is executed. This large amount of inertia results in the generation of excessive shock when the tool magazine starts and stops, thus making it difficult to precisely control the start-stop indexing action of the tool magazine at high speeds.
The invention proposes an automatically indexing tool magazine capable of transporting any one tool within a group of multiple tools to a specific tool pickup position, said tool magazine being structured so as to accommodate a large number of tools in a relatively small space and quickly transport tools to the tool removal station with a minimum inertial effect.
The tool magazine put forth by the invention is comprised of an indexing main table rotatably installed to a support frame, multiple indexing sub-tables rotatably installed in a radial pattern at uniform intervals on the aforesaid main table, multiple detachable tool pots installed in a radial pattern at uniform intervals on the aforesaid sub-tables, a main indexing mechanism installed to the aforesaid main table with the purpose of bringing the designated sub-table to the tool exchange station, and a sub-indexing mechanism installed to the aforesaid sub-table with the purpose indexing the sub-table to bring the designated tool pot to the tool exchange station.
This structure, in which multiple tool pots are installed to sub-tables which are in turn installed to a main table, not only allows a larger number of tools to be carried by the tool magazine, it reduces the overall size of the tool magazine to allow for more efficient space utilization at the site where the metal processing machine is used.
Moreover, this structure, in which groups of tools are carried separated by multiple sub-tables, reduces start-stop inertia by allowing the main and sub-tables to move independently only to the extent of the required indexing angle. The result is a smoother start-stop action of the main and sub-tables which in turn allows for faster indexing speed that has the effect of reducing tool transport time as means of increasing overall operating efficiency of the metal processing machine.
The aforesaid main indexing mechanism may be comprised of a main input shaft, a main output shaft used to transfer power to the main table, and cam driven reduction gearing that provides a rotational indexing control function based on an angular phase change command signal output from a rotational angle detection means installed at the aforesaid main input shaft or main output shaft. In the same manner, the aforesaid sub-indexing mechanism is comprised of a sub-input shaft, a sub-output shaft used to transfer power to the sub-table, and roller gear cam driven reduction gearing that provides a rotational control function based on an angular phase change command signal output from a rotational angle detection means installed at the aforesaid sub-input shaft or sub-output shaft.
The aforesaid structure is able to simultaneously index the main output shaft and sub-output shaft to the desired rotational angle, and to achieve a smooth rotational action of the main and sub-tables that has the effect of suppressing vibrations generated by the moving tool magazine that can be harmful to the machining process. Tool magazine service life is also extended due to the reduction in abrasional wear.
The aforesaid main and sub-indexing mechanisms may also be structured as a cam driven indexing mechanism that capable of imparting a smooth rotating action to the main and sub-tables to suppress vibrations generated by the moving tool magazine and to reduce abrasional wear within the tool magazine.
It is advantageous to manage the tool positions in the tool magazine by applying numbers to the main table and sub-tables so as to establish a matrix-type memory positional control system. In this way the position of each stored tool can be known in real time, thus allowing for an accurate positioning operation the next time that the tool is needed.
Moreover, additional tool pots may be installed to the main table between the sub-tables, thus further increasing the tool holding capacity of the tool magazine.
The aforesaid main indexing mechanism may incorporate a main output shaft as means of supplying rotational torque to the main table, and the sub-indexing mechanism may incorporate a sub-output shaft as means of supplying rotational torque to the sub-tables. Both of these main and sub-indexing mechanisms may be installed within a common housing in which the main output shaft resides within the sub-output shaft on the same rotational axis, or in which the sub-output shaft resides within the main output shaft on the same rotational axis as means of reducing the size of the main and sub-indexing mechanisms.
Tool transport time is significantly reduced because the main and sub-indexing mechanisms operate simultaneously to position the main and sub-tables.
A planetary gearset may be installed between the sub-indexing mechanism and sub-tables as means of transferring power from the sub-indexing mechanism to each sub-table, thus allowing a single sub-indexing mechanism to rotationally drive all sub-tables.
The aforesaid planetary gearset may be comprised of a centrally located rotating sun gear, a planetary gear fixedly installed to the circumference of each sub-table, and power transferring idler gears positioned between the aforesaid sun gear and planetary gears as means of transferring power between them. The aforesaid sun gear and planetary gears may be made to the same dimensions as means of maintaining a uniform rotating speed of both gears. In this case, as the rotational angle phase change of the sun and planetary gears is identical, the rotational angle of each sub-table can be easily controlled through that rotational angle of the sun gear.
The automatic tool removal position of the sub-table may be established by a structure through which the sub-indexing mechanism rotationally indexes only one sub-table without rotating the other sub-tables.
In this case, a sub-table connecting device is used at the indexed sub-table to enable the sub-indexing mechanism to be connected or disconnected to the sub-table as means of rotatably indexing only one sub-table.
The use of the aforesaid sub-table connecting device provides for a structure through which non-designated sub-tables (that is, sub-tables that are not holding the tool designated for indexing) are not rotated as a result of their being disconnected from the sub-table indexing mechanism, thus reducing rotating weight and the resulting undesirable inertial effect.
A reciprocating drive mechanism may be provided to move the sub-indexing mechanism up to the sub-table (when that sub-table is to be rotatably indexed by the sub-indexing mechanism) as means of connecting the sub-indexing mechanism to the sub-table. Furthermore, a coupling mechanism may be provided to temporarily connect the sub-indexing mechanism to the sub-table as means of transferring power from the sub-indexing mechanism to the sub-table.
This structure, by which the sub-indexing mechanism is able to connect to or disconnect from the sub-table, provides means whereby the sub-table and sub-indexing mechanism can be connected or disconnected as desired.
The aforesaid reciprocating drive mechanism may incorporate a cam drive unit as means of converting the rotational movement of the sub-indexing mechanism to a linear reciprocating movement, thus allowing the sub-indexing mechanism to generate both rotational torque and linear reciprocating movements.
The aforesaid reciprocating drive mechanism may be equipped with a slide unit as means of guiding the aforesaid reciprocating movement of the sub-indexing mechanism. This slide unit may be comprised of a slide frame that supports the reciprocating sliding movement of the sub-indexing mechanism, and a slider part installed to the sub-indexing mechanism and movably connected to the aforesaid slide frame as means of imparting a smooth and precise sliding action to the sub-indexing mechanism.
The aforesaid cam drive unit may incorporate a rotating cam powered by the rotational torque supplied to the sub-indexing mechanism, a cam profile as means of converting the aforesaid rotational torque to a linear reciprocating motion output by the sub-indexing mechanism, and a cam follower attached to the slide frame, said cam follower being in constant contact with the aforesaid rotating cam as means of generating the aforesaid reciprocating motion.
The aforesaid coupling mechanism may be comprised of releasable joint formed by the mutual interconnection of an angular protruding nub and corresponding recessed female part, said joint providing means of positionally aligning the sub-table with the sub-indexing mechanism.
The sub-indexing mechanism may be installed at the tool removal station and incorporate a sub-input shaft and sub-output shaft. In order to provide a releasable connection to the sub-table indexed at the tool removal position, a compound cam mechanism may be employed as means of converting the rotational movement from the sub-input shaft to the compound rotational and reciprocating movement of the sub-output shaft that rotationally indexes the sub-table.
The aforesaid compound cam mechanism utilizes an axially movable splined joint, located between the sub-input and sub-output shafts, as means of connecting a rotatable turret part to the sub-output shaft so as to allow the turret to move in the axial direction in relation to the sub-output shaft. The compound cam structure further utilizes a first cam mechanism as means of converting the rotational movement of the sub-input shaft to the rotational movement of the sub-output shaft; and a second cam mechanism, installed between the sub-input shaft and sub-output shaft, as means of converting the rotational movement of the sub-input shaft to the reciprocating movement of the sub-output shaft.
It is desirable to equip the main table with a radial indexing mechanism, installed at each of the sub-tables, as means of maintaining each sub-table at an indexed position. This radial indexing mechanism will improve the tool exchange operation by allowing each sub-table to always be oriented with a tool pot accurately aligned with the tool exchange station. The aforesaid radial indexing mechanism will also provide for precise connecting action of the reciprocating drive connector to the sub-table, and will also prevent the sub-tables from vibrating when the main table is turning. As a result, the position of the tool pots can always be maintaining at desired points and tools can be easily replaced even when a sub-table is not aligned with the tool removal station.
The aforesaid radial indexing mechanism incorporates a radial indexing structure fixedly installed to the sub-table, and a stop position control device, installed to the main table, that connects with the aforesaid radial indexing part to maintain the rotational position of the sub-table.
The aforesaid radial indexing structure incorporates a connecting part radially positioned in relation to each tool pot as means of establishing an accurate stop position for each tool pot.
The aforesaid position stop position control device incorporates a sliding block able to move toward and against the aforesaid connecting part, and a compressible element installed to the main table in a manner as to provide a force to move the aforesaid sliding block toward and against the aforesaid connecting part.
The tool magazine put forth by this application may also incorporate multiple moving track-type tool holders on which tools may be held instead of on the aforesaid sub-tables. That is, the tool magazine may also be comprised of
an indexing main table rotatably installed to a support frame, multiple indexing sub-tables rotatably installed in a radial pattern at uniform intervals on the aforesaid main table,
a drive part fixedly installed to each sub-table so as to revolve together with the sub-table,
a driven part rotatably installed to the main table,
a moving belt part installed around and between the aforesaid drive part and driven part,
multiple tool pots installed on the aforesaid moving belt part at uniform intervals,
an indexing mechanism connected to the main table with the purpose of rotating the main table to bring a designated belt part to the tool exchange station,
and a sub-table indexing mechanism, attached to a sub-table, that has the purpose of rotating the aforesaid moving belt part to bring the designated tool pot to the tool removal station.
The advantage of this structure is that it can increase the capacity of the tool magazine without increasing the magazine""s overall size.